A DGCR8/FLII-dominated on-off switch for immediate-early genes governs embryo implantation in mouse and human [Cut&Tag]
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ABSTRACT: As an essential checkpoint for successful pregnancy, mammalian embryo implantation initiates fetal-maternal communication. However, the underlying transcriptional regulation governing such a fast transition is still unknown. Here, we identify a DGCR8/FLII-dominated on-off switch for immediate-early genes (IEGs) governing pluripotency transition and morphogenesis of epiblasts upon embryo implantation. In mouse naïve embryonic stem cells (mESCs), we find the Microprocessor component DGCR8, but not DROSHA, can recognize mRNA stem-loop structures and further interact with and occupy transcriptional activator FLII to directly suppress transcription of non-miRNA target genes. Interestingly, when mESCs exit from naïve pluripotency, ERK signaling is quickly activated to induce FLII phosphorylation and disrupt DGCR8/FLII interaction. Phosphorylated FLII then binds to AP1, a typical IEG, to mediate the transcriptional activation of cell migration-related genes to establish poised pluripotency. Re-occupation of FLII by DGCR8 drives poised ESCs into formative pluripotency. Disruption of the DGCR8/FLII-mediated transcriptional activation inhibits the naïve-poised-formative ESC transition and the corresponding embryonic morphogenesis during implanting period, which is conserved in mouse and human.
Project description:As an essential checkpoint for successful pregnancy, mammalian embryo implantation initiates fetal-maternal communication. However, the underlying transcriptional regulation governing such a fast transition is still unknown. Here, we identify a DGCR8/FLII-dominated on-off switch for immediate-early genes (IEGs) governing pluripotency transition and morphogenesis of epiblasts upon embryo implantation. In mouse naïve embryonic stem cells (mESCs), we find the Microprocessor component DGCR8, but not DROSHA, can recognize mRNA stem-loop structures and further interact with and occupy transcriptional activator FLII to directly suppress transcription of non-miRNA target genes. Interestingly, when mESCs exit from naïve pluripotency, ERK signaling is quickly activated to induce FLII phosphorylation and disrupt DGCR8/FLII interaction. Phosphorylated FLII then binds to AP1, a typical IEG, to mediate the transcriptional activation of cell migration-related genes to establish poised pluripotency. Re-occupation of FLII by DGCR8 drives poised ESCs into formative pluripotency. Disruption of the DGCR8/FLII-mediated transcriptional activation inhibits the naïve-poised-formative ESC transition and the corresponding embryonic morphogenesis during implanting period, which is conserved in mouse and human.
Project description:As an essential checkpoint for successful pregnancy, mammalian embryo implantation initiates fetal-maternal communication. However, the underlying transcriptional regulation governing such a fast transition is still unknown. Here, we identify a DGCR8/FLII-dominated on-off switch for immediate-early genes (IEGs) governing pluripotency transition and morphogenesis of epiblasts upon embryo implantation. In mouse naïve embryonic stem cells (mESCs), we find the Microprocessor component DGCR8, but not DROSHA, can recognize mRNA stem-loop structures and further interact with and occupy transcriptional activator FLII to directly suppress transcription of non-miRNA target genes. Interestingly, when mESCs exit from naïve pluripotency, ERK signaling is quickly activated to induce FLII phosphorylation and disrupt DGCR8/FLII interaction. Phosphorylated FLII then binds to AP1, a typical IEG, to mediate the transcriptional activation of cell migration-related genes to establish poised pluripotency. Re-occupation of FLII by DGCR8 drives poised ESCs into formative pluripotency. Disruption of the DGCR8/FLII-mediated transcriptional activation inhibits the naïve-poised-formative ESC transition and the corresponding embryonic morphogenesis during implanting period, which is conserved in mouse and human.
Project description:As an essential checkpoint for successful pregnancy, mammalian embryo implantation initiates fetal-maternal communication. However, the underlying transcriptional regulation governing such a fast transition is still unknown. Here, we identify a DGCR8/FLII-dominated on-off switch for immediate-early genes (IEGs) governing pluripotency transition and morphogenesis of epiblasts upon embryo implantation. In mouse naïve embryonic stem cells (mESCs), we find the Microprocessor component DGCR8, but not DROSHA, can recognize mRNA stem-loop structures and further interact with and occupy transcriptional activator FLII to directly suppress transcription of non-miRNA target genes. Interestingly, when mESCs exit from naïve pluripotency, ERK signaling is quickly activated to induce FLII phosphorylation and disrupt DGCR8/FLII interaction. Phosphorylated FLII then binds to AP1, a typical IEG, to mediate the transcriptional activation of cell migration-related genes to establish poised pluripotency. Re-occupation of FLII by DGCR8 drives poised ESCs into formative pluripotency. Disruption of the DGCR8/FLII-mediated transcriptional activation inhibits the naïve-poised-formative ESC transition and the corresponding embryonic morphogenesis during implanting period, which is conserved in mouse and human.
Project description:As an essential checkpoint for successful pregnancy, mammalian embryo implantation initiates fetal-maternal communication. However, the underlying transcriptional regulation governing such a fast transition is still unknown. Here, we identify a DGCR8/FLII-dominated on-off switch for immediate-early genes (IEGs) governing pluripotency transition and morphogenesis of epiblasts upon embryo implantation. In mouse naïve embryonic stem cells (mESCs), we find the Microprocessor component DGCR8, but not DROSHA, can recognize mRNA stem-loop structures and further interact with and occupy transcriptional activator FLII to directly suppress transcription of non-miRNA target genes. Interestingly, when mESCs exit from naïve pluripotency, ERK signaling is quickly activated to induce FLII phosphorylation and disrupt DGCR8/FLII interaction. Phosphorylated FLII then binds to AP1, a typical IEG, to mediate the transcriptional activation of cell migration-related genes to establish poised pluripotency. Re-occupation of FLII by DGCR8 drives poised ESCs into formative pluripotency. Disruption of the DGCR8/FLII-mediated transcriptional activation inhibits the naïve-poised-formative ESC transition and the corresponding embryonic morphogenesis during implanting period, which is conserved in mouse and human.
Project description:Naïve pluripotency is sustained by a self-reinforcing gene regulatory network (GRN) comprising core and naïve pluripotency-specific transcription factors (TFs). Upon exiting naïve pluripotency, ES cells transition through a formative post-implantation-like pluripotent state. However, the mechanisms underlying disengagement from the naïve GRN and initiation of the formative GRN remain unclear. Here, we demonstrate that phosphorylated AKT acts as a gatekeeper that prevents nuclear localization of FoxO TFs in naïve ESCs. PTEN-mediated reduction of AKT activity allows nuclear entry by FoxO TFs, enforcing a cell fate transition by binding and activating formative pluripotency-specific enhancers. Indeed, FoxO TFs are necessary and sufficient for transition from the naïve to the formative pluripotent state. Our work uncovers a pivotal role for FoxO TFs and AKT signalling in mechanisms underlying the exit from naïve pluripotency, a critical early embryonic cell fate transition.
Project description:Naïve pluripotency is sustained by a self-reinforcing gene regulatory network (GRN) comprising core and naïve pluripotency-specific transcription factors (TFs). Upon exiting naïve pluripotency, ES cells transition through a formative post-implantation-like pluripotent state. However, the mechanisms underlying disengagement from the naïve GRN and initiation of the formative GRN remain unclear. Here, we demonstrate that phosphorylated AKT acts as a gatekeeper that prevents nuclear localization of FoxO TFs in naïve ESCs. PTEN-mediated reduction of AKT activity allows nuclear entry by FoxO TFs, enforcing a cell fate transition by binding and activating formative pluripotency-specific enhancers. Indeed, FoxO TFs are necessary and sufficient for transition from the naïve to the formative pluripotent state. Our work uncovers a pivotal role for FoxO TFs and AKT signalling in mechanisms underlying the exit from naïve pluripotency, a critical early embryonic cell fate transition.
Project description:Naïve pluripotency is sustained by a self-reinforcing gene regulatory network (GRN) comprising core and naïve pluripotency-specific transcription factors (TFs). Upon exiting naïve pluripotency, ES cells transition through a formative post-implantation-like pluripotent state. However, the mechanisms underlying disengagement from the naïve GRN and initiation of the formative GRN remain unclear. Here, we demonstrate that phosphorylated AKT acts as a gatekeeper that prevents nuclear localization of FoxO TFs in naïve ESCs. PTEN-mediated reduction of AKT activity allows nuclear entry by FoxO TFs, enforcing a cell fate transition by binding and activating formative pluripotency-specific enhancers. Indeed, FoxO TFs are necessary and sufficient for transition from the naïve to the formative pluripotent state. Our work uncovers a pivotal role for FoxO TFs and AKT signalling in mechanisms underlying the exit from naïve pluripotency, a critical early embryonic cell fate transition.
Project description:In the mammalian embryo, epiblast cells must exit the naïve state and acquire formative pluripotency. This cell state transition is recapitulated by mouse embryonic stem cells (ESCs), which undergo pluripotency progression in defined conditions in vitro. However, our understanding of the molecular cascades and gene networks involved in the exit from naïve pluripotency remains fragmentary. Here, we employed a combination of genetic screens in haploid ESCs, CRISPR/Cas9 gene disruption, large-scale transcriptomics and computational systems biology to delineate the regulatory circuits governing naïve state exit. Transcriptome profiles for 73 ESC lines deficient for regulators of the exit from naïve pluripotency predominantly manifest delays on the trajectory from naïve to formative epiblast. We find that gene networks operative in ESCs are also active during transition from pre- to post-implantation epiblast in utero. We identified 496 naïve state-associated genes tightly connected to the in vivo epiblast state transition and largely conserved in primate embryos. Integrated analysis of mutant transcriptomes revealed funnelling of multiple gene activities into discrete regulatory modules. Finally, we delineate how intersections with signalling pathways direct this pivotal mammalian cell state transition.
Project description:The embryonic stem cell (ESC) transition from naive to primed pluripotency is marked by major changes in cellular properties and developmental potential. ISY1 is implicated in miRNA biogenesis yet its widespread role and relevance to ESC biology remain unknown. Here we find that highly dynamic ISY1 expression during the naïve to primed ESC transition defines a unique phase of ‘poised’ pluripotency characterized by distinct miRNA and mRNA transcriptomes and widespread poised cell contribution to mouse chimeras. Loss- and gain-of-function experiments reveal that ISY1 promotes exit from the naïve state, is necessary and sufficient to induce and maintain poised pluripotency, and that persistent ISY1 overexpression inhibits the transition from the naïve to the primed state. We identify a large subset of ISY1-dependent miRNAs that can rescue the inability of miRNA-deficient ESCs to establish the poised state and transition to the primed state. Thus, dynamic ISY1 regulates poised pluripotency through miRNAs to control ESC fate.
Project description:Human naïve pluripotent stem cells (PSC) share features with pre-implantation epiblast. They thus provide an unmatched opportunity for characterising the developmental programme of pluripotency in Homo sapiens. Here we confirm that naïve PSC do not respond directly to germ layer induction, but must first acquire competence. Capacitation for multi-lineage differentiation occurs without exogenous growth factor stimulation and is facilitated by inhibition of Wnt signalling. Whole transcriptome profiling during this formative transition highlights dynamic changes in gene expression, affecting many cellular properties, including metabolism and epithelialisation. Notably, naïve pluripotency factors are exchanged for post-implantation factors, but competent cells remain devoid of lineage primed transcription. The gradual pace of transition for human naïve PSC is consistent with the timespan of primate development from blastocyst to gastrulation. Transcriptome trajectory during in vitro capacitation of human naïve cells tracks the progression of epiblast during embryogenesis in Macaca fascicularis, but shows greater divergence from mouse development. Thus the formative transition of naïve PSC in a simple culture system may recapitulate essential and specific features of pluripotency dynamics during an inaccessible period of human embryogenesis.